OK - I just installed a Radeon 9800pro a few weeks ago and so far no problems. Recently, though, it has been doing the following : I'm in the middle of a game and randomly everything thats happening stops all of a sudden and my monitor goes into a sleep mode if you will. The monitor goes from the green (on) to the orange color buttons. The only thing that works is to power the PC down and restart it. Last time it happened (about 5 minutes ago) someone was talking on vent and I was playing a game with them and he got cut off as soon as the monitor went black. the computer is still running but everything that was happening stops happening.

is my computer getting too hot or is the 300w psu not holding up? (i suppose its a psu, it was a cheap computer).

cpu running @ 46, but it IS a amd sempron, so that should be normal. mother board running at 40 though. mabye 46 is a little too hot for just a few firefox windows open.

I had the same problem happen on my old computer, and it was right after I switched video cards. I found out for some reason my motherboard/BIOS was not compatible and I had to take the new video card out.

You might want to try replacing the new card with an older one thats known to work and see if it happens again.